JNTU
JNTU B.Tech II METALLURGY AND MATERIALS ENGINEERING Previous Question Paper (May/June - 2019 - R15)
Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit.
Part A
What is equivalent carbon in cast iron? How this term is useful?
Answer
Equivalent carbon (CE) is a measure of the total effect of carbon and other alloying elements on the hardenability and castability of cast iron, typically calculated as CE = %C + (%Si + %P)/3. It is useful for predicting the microstructure, mechanical properties, and weldability of the material, effectively normalizing the influence of various elements to that of carbon.
Why is it easier to control the properties of cast irons as compared to steels? Explain covering all points with respect to the above.
Answer
Cast irons are easier to control because they have a lower melting point and higher fluidity due to their near-eutectic composition, allowing for complex shape casting. Furthermore, the presence of high carbon and silicon content allows for significant microstructural control through cooling rate adjustments and inoculation, which can dictate the formation of graphite (flake, nodular, or malleable) versus cementite, providing a wider range of properties than the more restricted carbon range of steels.
What are the effects of non-equilibrium cooling of alloys?
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Why nickel and copper show continuous solid solubility in each other?
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"The ratio of ferrite to cementite in pearlite is constant." Explain.
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Why age hardening process is two step process?
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Write the principle of sintering process.
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Explain the principle of flame hardening method.
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What is condensation polymerization? Explain with example.
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What is degree of polymerization? Explain its significance.
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Part B
Briefly explain properties and applications of the following:
Grey cast Iron
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Low alloy steels.
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Explain the factors that influence the microstructure and properties of cast irons.
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Explain the composition, microstructure and properties of Austenitic stainless steels.
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Explain the cooling behavior of 0.4 wt% carbon steels. Draw the microstructure at each levels.
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Construct the Isomosphous system with the help of cooling curves.
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What is coring? How it can be eliminated?
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Differentiate between Annealing and normalising heat treatments.
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Explain with neat sketch the pack carburizing methods with suitable example.
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Explain the property and structural changes during cold working and annealing of metals.
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What is critical degree of cold work? Explain.
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Distinguish between Intrinsic semiconductors and extrinsic semiconductors.
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State and explain the Fick’s law of diffusion.
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Explain the principle and application of Nitriding process.
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Write short notes on the application of diffusion process.
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List the traditional ceramics and write the properties and applications of it.
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What factors affect the crystallization of polymers?
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Differentiate between thermoplastic polymers and thermosetting polymers. Give minimum two examples of each type.
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Define composite. Explain the properties and applications of composites.
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